BIO 1140 Lecture Notes - Lecture 4: Threonine, Plasmodesma, Glycogen Phosphorylase
30 Oct 2016
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Document Summary
Direct gap junctions and plasmodesmata: direct cytoplasmic link for small molecules to pass through. Hormones: synthesized by specialized cells called endocrine cells, released in the extracellular environment and carried to a distant cell, paracrine messengers act locally. Released by a signalling cell and act on the neighboring cells: neurotransmitters and neurohormones. Multiple tissues responding in different ways to a single molecule signal. First messenger released by the signalling cell into the extracellular environment: acts on target cells, that have the receptor to recognize the signal. Cell have a whole range of receptors, more receptors stronger response, less weaker response. Cellular response: changes in gene expression, changes in protein activity, takes time for these changes to take place, protein function can be altered by signalling pathways, responses are specific to the cell, different pathways are turned on. In cancer signalling pathways promoting cell growth are turned on and never turned off.
